Apparatus for forming a rolled edge on containers made of sheet material



April 11, 1967 G E. DURAT 3,313,220

R. APPARATUS FOR FORMING A ROLLED EDGE ON CONTAINERS MADE OF SHEETMATERIAL Filed Jan. 27, 1965 5 Sheets-Sheet 1 April 11, 1967 R. G. E.DURAT 3,313,220

APPARATUS FOR FORMING A ROLLED EDGE ON CONTAINERS MADE OF SHEET MATERIALFiled Jan. 27, 1965 5 Sheets-Sheet 2 5 Sheets-Sheet 5 Apni 11, 1967 R.G. E. DURAT APPARATUS FOR FORMING A ROLLED EDGE ON CONTAINERS MADE OFSHEET MATERIAL Filed Jan. 27, 1965 United States Patent C i 3,313,220APPARATUS FUR FORMING A RGLLED EDGE N CQNTAINERS MADE 0F SHEET MATERIALRobert Georges Eugene Durst, JOuet-sur-lAubois, France Fiied Jan. 27,1965, Ser. No. 428,324 Ilaims priority, application France, June 3,1964,

76,876, Patent 1,4059% Claims. (Cl. 93-365) In the manufacture ofcontainers made of sheet material such as paper or cardboard, which maybe previously coated or not, it is usual for the free edge of thecontainer to be rolled, thereby ensuring smoother pouring of thecontents, and, in cases where the contents are absorbed straight fromthe container, a more agreeable sensation for the lips.

In most devices used for forming rolled edges, the sheet material usedfor the container penetrates into a fixed rolling groove which restrainsthe material over the outer surface of the rolled edge.

Whereas such rolled edges can readily be formed with conventionalapparatus when the diameter of the opening in the container to beprovided therewith is relatively large, the operation becomes far moredelicate when the diameter referred to is relatively small, andparticularly when frusto-conical containers with open smaller bases areinvolved. Due to the restraining action to which the rolled edge issubmitted on its external surface during the rolling operation, thesheet material used for the container is subjected to considerablestresses owing to the fact that the rolling diameter of the rolled edgerepresents a relatively large fraction of the diameter of the opening.This results in tears or cracks in the sheet material, which are all themore detrimental in that the latter is previously coated with aprotective lining. Furthermore, it is impossible to hot-roll an edgewhen polyethylene (hereinafter called polythene) is used, although thisis cutomary procedure with ordinary cardboard.

The main object of the present invention is to overcome these drawbacksand to provide fully cold-rolled edges in a single operation. For thispurpose, the present invention provides an apparatus for forming rollededges on containers made of sheet material, comprising, on the one hand,rolling means consisting of a central part having thereon an externalcircular throat of quarter-circle section and of jaws mounted underlight friction on the support of said central part, which are radiallyslidable behind the same and have formed on their inner faces an arcuategroove of semi-circular cross-section that jointly form with said throata hollow toroidal rolling die, and, on the other hand, means for axiallymoving said rolling means toward the container mounted on a fixedcoaxial support whereby to roll down its edge in said die, means foropening said jaws after formation of the rolled edge and means forclosing them anew after said rolling means recede from the containerformed with its rolled edge.

Thus, as the rolling means move toward the container and the sheetmaterial forming the latter is rolled back in the rolling die, and asthe rolling diameter gradually increases, said jaws are displaced bysliding radially against their restraining friction and thereby nolonger clamp the material formed into a rolled edge.

The description which follows with reference to the accompanyingnon-limitative exemplary drawings will give a clear understanding of howthe invention can be carried into practice.

In the drawings:

FIG. 1 shows in axial section the apparatus for forming the rolled edgesaccording to the invention in the inoperative position.

FIG. 2 is a fragmental view corresponding to FIG. 1, showing the rollededge being formed.

3353,229- Paitenteii 1 1 1 967 FIG."3is 'afragmental view similar toFIG. 1, after completion of the rolled edge, when the latter is about tobe disengaged from the apparatus.

FIG. 4 is a fragmental view similar to FIG. 1, after completion of therolled edge and the reverting of the apparatus to the inoperativeposition.

FIG. 5 is a view of the jaw-bearing web looking in the direction of thearrow F of FIG. 4, showing the three component parts of a jaw positioneddifferently for illustrative purposes; and

FIG. 6 is a partial diametrical section, on an enlarged scale, through acontainer with a finished rolled edge.

The purpose of the apparatus shown in the accompanying drawings is toform a rolled edge on the opening 1 of a frusto-conical container 2 openover its smaller base. This container is mounted in a fixed support 3and centered thereon by a hollow frusto-conical part 4. The larger baseof the container bears on a surface 5 consisting, say, of the thrustface of a tool used to complete the fitting of the container bottom.

The means for forming the rolled edge include a hollow tool-carrier 6coaxial with the part 4 and fixed through a base 7 to a fixed support 8.Through the medium of screws 9, the carrier 6 supports a bell-mouth 10along the lip of which is formed an internal chamfer 11.

Within the tool-carrier 6 is fitted a hollow slidable part 12 formingthe tool shank and terminating in a jaw-bearing web 13. Within the toolshank 12 is mounted an arbor one end of which is formed as a cam withsix inclined facets 16 acting as a multiple wedge. Against theseinclined facets 16 bear angularly-shaped slides 17 having an apex angleof 60 and terminating at their outer ends in chamfers 14 which, in theinoperative position, engage with the chamfer 11 on the bell-mouth 10.Each slide is retained on the jaw-bearer 13 by a screw 20, a spring 21being interposed between the head of this screw and a washer 22 bearingagainst the rear face of the web 13. Each screw extends through anoblong opening 23 formed in the web 13, thereby acting as guide meansfor the corresponding slide 17.

Secured to each slide 17 by a screw 24 is a part 25 for restraining theassociated jaw, which part is centered on the corresponding slide 17 byan arcuate tenon' 26 cooperating with a mortise 27 formed in that slide.Between each slide 17 and each restraining part 25 is mounted a jaw 28made of anti-friction material, set into a lodging 29 in the slide andformed with an arcuate rib 36 engaging in a matching groove in the part25. The assembly consisting of each part 25 and the corresponding jaw 28and slide 17 thus forms a whole capable of moving radially over thejaw-bearing web 13.

Each jaw terminates adjacent the center in a fiat portion 31 which is incontact with the larger base of a frusto-conical part 32 inanti-friction material centered on the main axis of the apparatus andprovided with a cylindrical base 58 for centering the jaws. This part 32is spring-loaded against the jaws 31 and the slides 17 by a screw 33which is carried by the arbor 15 and beneath the head of which isdisposed a spring 34 pressing a thrust washer 35 against the smallerbase of frusto-conical part 32. Adjacent its larger base thisfrusto-conical part has formed thereon a toroidal throat 36 having aquartercircle section which is extended over the jaws, in theinoperative position, by an arcuate groove 37 of semicircular sectionthe front edge of which is spaced from the external conical surface ofthe part 32. The throat as and the groove 37 jointly form a rolling die.

At its end remote from its web 13, the tool shank 12 terminates in acylindrical recess 38 and in an external screw thread 39 onto which arescrewed a nut 41) and a locknut 41. The arbor 15 terminates in a sectionof smaller diameter 42 having thereon a terminal screw thread 43 ontowhich are screwed two nuts 44 and 45 which clamp between them a part 46provided with an upper lug 47 and a lower arm 48. Fitted over thesection 42 of the arbor 15, between the bottom of the recess 38 and thenut 44, is a spring 49 which urges the arbor 15 away from the tool shank12 and the jaws until a pin 6a. rigid with the shank butts against thefront end of an opening 15a extending through the arbor 15. A secondspring 50 of lesser strength than the spring 59 connects the lug 47 to afixed point 51 and biases the tool assembly rearwardly. On the lever 48is pivotally mounted a link 52 the other end of which is pivotallyconnected to a lever 53 fulcrumed about a fixed shaft 54. The lever 53carries a follower 55 urged by the spring 50 against a cam 56 mounted onthe apparatus actuating shaft 57.

The apparatus hereinbefore described operates in the following manner:

Referring to the configuration of FIG. 1, in which the container 2 hasbeen mounted in its support 4 with its bottom pressing against the fixedsurface 5, when the drive shaft 57 is set in operation, the part 46, inresponse to the cam 56, exerts a thrust against the bottom of the recess33 through the agency of the spring 49. This spring is sufiicientlystrong to transmit without being compressed the force required to rolldown the edge of the container and allow the apparatus to adopt theconfiguration of FIG. 2, in which the nut 40 butts against thetool-carrier 6.

In the course of this motion, the tool shank 12 will have moved togetherwith the arbor 15 through the toolcarrier 6, thereby causing theedge-rolling means to project from the fixed bell-mouth 10. Thecontainer edge 1 is guided by the outer surface of the frusto-conicalpart 32 and caused to penetrate into the rolling die formed by thethroat 36 and the grooves 37. Subsequently, as the edge-rolling meansmove toward the container, the edge is rolled back onto itself in saiddie, with the throat 36 fulfilling a prerolling function. As the rollingdiameter increases, the material used for the container moves externallythe jaws 28 against the countering friction exerted by the washers 22responsively to the springs 21, as shown in FIG. 2. The rolled edge isthus formed without any constraint being applied to it by the jawswhich, by virtue of their radial shift, provide a slight clearancebetween their faces and the cylindrical base 58 of the frustoconicalpart 32, between the bearing faces ofthe slides 17 and the inclinedfacets 16, and between the ends of the oblong openings 23 and the screws20.

As the cam 56 continues to rotate, the spring 49 is compressed by thenut 44, causing the arbor 15 to be moved. Through its terminal inclinedfacets 16, the arbor 15 causes the compound consisting of the slides 17,the jaws 28 and their restraining parts 25 to recede radially, saidcompound being guided by the screws 20 sliding through the openings 23.This radial recession is effected over a distance such that the frontedges of the arcuate grooves 37 of semi-circular section move backsufficiently to permit the rolled edge 59 to be disengaged from therolling means (see FIG. 3). Said compound is restrained in the withdrawnor open position by reason of the friction of the washers 22 loaded bythe springs 21.

As the cam 56 rotates further, the compound is returned to the positionof FIG. 4 responsively to the reaction of the spring 59, the spring 49having meanwhile caused the arbor 16 to withdraw through the tool shank6 until the pin 6a contacts the forward edge of the opening 15a. Theinternal chamfer 11 on the bell-mouth simultaneously fetches the jawsinto their closed inoperative position by coacting with the externalchamfers 14 on the slides 17.

During the advance and withdrawal of the multiple wedge, thefrusto-conical part 32 is held centered by the friction which is exertedon it by the plate 35 responsively to the spring 34. r

Preferably, the jaws 23. and the frusto-conical part 32 are made of asynthetic resin of the polytetrafluoroethylene class, an example beingthe resin known by the trade name Teflon.

There is thereby obtained a rolled edge free from creases, tears orcracks if the sheet material used for the container is provided with alining such as a thermoplastic lining and most notably a polythenelining, thereby giving the container at most pleasing appearance.

Preferably, the seal down the side of the sheet material forming thecontainer is made in the manner described in the U.S. Patent ApplicationSerial No. 428,295 filed this day by the Applicant and entitled Methodand Apparatus for Leaktightly Joining Materials in Sheet Form, in orderthat the jaw facing this seal should not be displaced to an unduly largeextent relatively to the displacement of the other jaws and therebydetract from the appearance of the rolled-down edge.

The apparatus according to the present invention can be used for formingrolled edges on frusto-conical containers and cylindrical containersalike. In the case of frusto-conical containers having their larger baseopen, the apparatus is supplemented by means for restraining thecontainer internally against its fixed support.

What I claim is:

1. An apparatus for forming a rolled edge on a container in sheetmaterial having a shape of revolution and mounted on a fixed support,comprising, in combination, a central part which is centered on the axisof the container mounted on its fixed support and which has formedthereon rearwardly of its perimeter an arcuate throat of quarter-circlesection at a distance from said axis equal to the distance therefrom ofthe container edge on which the rolled edge is to be formed; movablehollow support means coaxial with said part and defining a space withthe rear portion of said part; a plurality of jaws mounted on saidsupport means, radially movable in said space, in contact with saidcentral part and said support means, and projecting radially and forwardof the perimeter of said central part, said jaws being provided facingsaid part and on their forwardly projecting portion with an arcuategroove of semicircular section which, when said jaws are in theirretracted position, forms with said throat a rolling die ofthree-quarter torus shape open toward said container; means for applyingsaid jaws against said support means under slight pressure; means forapplying said central part against said jaws under slight pressure;means for displacing said support means axially toward said containerwhereby to roll down the edge thereof in said die outwardly of thecontainer and move said support means away from the container afterformation of the rolled edge; means for displacing said jaws radiallybetween said support means and said central part on completion of therolled edge whereby to open said die; means for reclosing said jaws whensaid support means has moved away from the container formed with itsrolled edge; and control means of said two displacing means.

2. An apparatus according to claim 1, wherein said central part isfrusto-conical and has the surface of its smaller face facing thecontainer, said throat being formed over its frusto-conical surfaceadjacent its larger base, the forward-projecting portions of the jawseach having a forwardly tapering frusto-conical face which jointlysurround said frusto-conical surface, and said groove being formed oneach of said frusto-conical jaw faces adjacent its larger base.

3. An apparatus according to claim 1, wherein said central part and saidjaws are made of anti-friction material.

4. Apparatus according to claim 3, wherein said antifriction material isa synthetic resin of the polytetrachloroethylene class.

5. Apparatus according to claim 1, wherein the means for displacing thejaws radially include a multiple wedge which is in contact with saidjaws and slides axially through said hollow support means.

6. An apparatus for forming a rolled edge on a container in sheetmaterial having a shape of revolution and mounted on a fixed support,comprising, in combination, a hollow t-ool shank which is coaxial withthe axis of the container mounted in its fixed support and terminates ina web facing the container; a fixed tool-carrier through which said toolshank slides and projects therefrom on either side and which has formedthereon a bell-mouth encompassing said web in the inoperative position;abutment means on said tool shank positioned remotely from said web forcontacting said fixed tool-carrier; a hollow frusto-conical central partpositioned forward of said web in the direction of the container Withits smaller base facing the same and having on its frusto-conicalsurface adjacent its larger base a circular throat of quarter-circlesection at a distance from said axis equal to the distance therefrom ofthe container edge to be rolled back; a plurality of jaws mounted onsaid web between it and said frusto-conical central part, said jawsbeing accommodated in said bell-mouth in the inoperative position, beingradially displaceable in contact with said central part and said web,and projecting radially and forwardly of the perimeter of said centralpart, each with a forwardly tapering face which jointly surround thefrusto-conical surface of said central part, said face having formedthereon a circular segment shaped groove of semi-circular cross-sectionadjacent its larger base, said groove and said throat jointly formingwhen said jaws are in their retracted position an edge-rolling die ofhollow threequarter-torus shape open in the direction of the container;means for applying said jaws against said web under slight pressure;means for applying said central part against said jaws under slightpressure; an arbor slidable through said tool shank, which terminates atits front end in inclined facets in contact with said jaws and whichprojects rearwardly from said tool shank; means for connecting saidarbor to said tool shank while enabling it to slide therethrough;reciprocating actuating means coupled to the projecting portion of saidarbor whereby to consecutively control axial displacement of said toolshank toward the container whereby to roll back the edge thereof in saiddie outwardly of the container, radial displacement of said jawsresponsively to said inclined facets on completion of the rolled edgewhereby to open said die, and recession of said support means from thecontainer after formation of the rolled edge; and means for reclosingsaid jaws after said tool shank has receded from the container formedwith its rolled edge.

7. Apparatus according to claim 6, wherein said web has formed in itsopposite each jaw an oblong opening and wherein the means for applyingsaid jaws under slight pressure against said web include, for each jaw,a screw fixed to the jaw and extending through the corresponding oblongopening, a thrust washer threaded over said screw and contacting the webface remote from the jaws, and a spring interposed between said thrustwasher and the screw head.

8. Apparatus according to claim 6, wherein the means for applying saidcentral part under slight pressure against said jaws comprise a screwwhich is fixed into the arbor end formed with inclined facets and whichprojects from said central part, a thrust washer threaded over thisscrew and contacting the forward face of said central part, and a springinterposed between this thrust washer and the head of said screw.

9. Apparatus according to claim 6, wherein said arbor has an openingformed through its portion contained within said tool shank and whereinthe means for connecting this arbor to the tool shank include a pinrigid with the shank and extending through said opening, means fordirectly connecting the projecting portion of said arbor to saidreciprocating actuating means, and a spring interposed between said toolshank and said connecting means of strength sufiicient to transmit theforce required to roll back the edge of the container.

10. Apparatus according to claim 6, wherein the rim of said bell-mouthis chamfered internally, said jaws having formed along their perimetersa matching external chamfer adapted to engage with said internalbell-mouth chamfer whereby to reclose said jaws when said tool shankrecedes from the container formed with its rolled edge.

References Cited by the Examiner UNITED STATES PATENTS 2,473,836 6/1949Wixon et a1 93-365 2,778,287 1/1957 Moore 93-365 2,819,658 1/1958 Scottet a1. 9336.'5

WILLIAM W. DYER, JR., Primary Examiner. JAMES M. MEISTER, Examiner.

1. AN APPARATUS FOR FORMING A ROLLED EDGE ON A CONTAINER IN SHEETMATERIAL HAVING A SHAPE OF REVOLUTION AND MOUNTED ON A FIXED SUPPORT,COMPRISING, IN COMBINATION, A CENTRAL PART WHICH IS CENTERED ON THE AXISOF THE CONTAINER MOUNTED ON ITS FIXED SUPPORT AND WHICH HAS FORMEDTHEREON REARWARDLY OF ITS PERIMETER AN ARCUATE THROAT OF QUARTER-CIRCLESECTION AT A DISTANCE FROM SAID AXIS EQUAL TO THE DISTANCE THEREFROM OFTHE CONTAINER EDGE ON WHICH THE ROLLED EDGE IS TO BE FORMED; MOVABLEHOLLOW SUPPORT MEANS COAXIAL WITH SAID PART AND DEFINING A SPACE WITHTHE REAR PORTION OF SAID PART; A PLURALITY OF JAWS MOUNTED ON SAIDSUPPORT MEANS, RADIALLY MOVABLE IN SAID SPACE, IN CONTACT WITH SAIDCENTRAL PART AND SAID SUPPORT MEANS, AND PROJECTING RADIALLY AND FORWARDOF THE PERIMETER OF SAID CENTRAL PART, SAID JAWS BEING PROVIDED FACINGSAID PART AND ON THEIR FORWARDLY PROJECTING PORTION WITH AN ARCUATEGROOVE OF SEMICIRCULAR SECTION WHICH, WHEN SAID JAWS ARE IN THEIRRETRACTED POSITION, FORMS WITH SAID THROAT A ROLLING DIE OFTHREE-QUARTER TORUS SHAPE OPEN TOWARD SAID CONTAINER; MEANS FOR APPLYINGSAID JAWS AGAINST SAID SUPPORT MEANS UNDER SLIGHT PRESSURE; MEANS FORAPPLYING SAID CENTRAL PART AGAINST SAID JAWS UNDER SLIGHT PRESSURE;MEANS FOR DISPLACING SAID SUPPORT MEANS AXIALLY TOWARD SAID CONTAINERWHEREBY TO ROLL DOWN THE